Multi-walled structure and method of assembly



Jan. 24, 1967 P. H. KELLERT 3,299,594

MULTI-WALLED STRUCTURE AND METHOD OF ASSEMBLY 2 Sheets-Sheet 1 Filed De o 16, .1963

. l Man INVENTOR.

PAUL H. KELLERT ATTORNEYS Jan. 24, 1967 P, H. KELLERT 3,299,594

MULTI-WALLED STRUCTURE AND METHOD OF ASSEMBLY Filed Dec. 16, 1963 2 Sheets-Sheet 2 INVENTOR. PAUL H. KELLERT BY M 1 J00 ATTORNEYS United States Patent 3,299,594 MULTI-WALLED STRUCTURE AND METHOD OF ASSEMBLY Paul H. Kellert, Mannford, Okla. 74044 Filed Dec. 16, 1963, Ser. No. 330,912 Claims. (Cl. 52-262) This invention relates to an improved building construction and method of assembling same. More specifically this invention relates to an improved building construction that is quickly and easily assembled to form a finished structure of variable design, having hollow core walls.

An object of this invention is to provide a building construction that is easily and quickly assembled and is easily redesigned.

Another object of this invention is to provide a building construction that, when assembled, has an attractive interior that need not be improved upon by additional construction.

Still another object of this invention is to provide a building construction that can be assembled to form a structurally complete construction in considerably less time than required to build a similar construction using conventional methods.

Yet another object of this invention is to provide a building construction that is structurally sturdy yet is assembled using a minimum amount of nails, bracing and the like.

A further object of this invention is to provide a basic building construction that can be used in constructing exterior and interior, either solid or hollow core walls.

Still a further object of this invention is to provide a building construction in which the basic construction elements are tooled in finished form, therefore, a construction thus erected needs no finished trim to complete its beauty.

Yet a further object of this invention is to provide a building construction that can be used with plastics, aluminum, steel, wood, or any other building construction material.

Yet another object of this invention is to provide a building construction in which interior partition walls formed thereby can be disassembled and moved with a minimum of time by reversing the procedure of assembly and then reassembling in the desired location.

Still a further object of this invention is to provide a building construction that can be used to construct a second new wall covering a pre-existing old wall which is especially advantageous when redecoratin g or redesigning old structures.

Another object of this invention is to provide a method of assembling a building construction of the type above mentioned that is relatively simple, fast and requires a minimum number of persons to perform the assembly.

Further objects and advantages of this invention will be apparent from the following description and appended claims, reference being bad to the accompanying drawings forming a part of this specification wherein like reference "ice FIGURE 5 is an exterior View of a modified bottom beam of the building construction of this invention.

FIGURE 6 is an exterior view of a modified top beam of the building construction of this invention.

FIGURE 7 is a transverse cross section view of a Wall formed of the building construction of this invention.

FIGURE 8 is a transverse cross section view of a wall tie-in element for connecting an interior partition wall to an exterior wall of the building construction of this invention.

This building construction consists in general of a bottom beam laid out in the outline of the exterior walls of the structure to be formed of this building construction; a top beam spaced vertically above the bottom beam and in the same outline as the bottom beam; one or more spaced apart vertical wall elements attached at their upper ends to the top beam and at their lower ends to the bottom beam; a vertical corner element located at each corner of the structure, attached at its upper end to the top beam and at its lower end to the bottom beam; and at least one wall panel located in each of the spaces bounded by the bottom beam, top beam, corner element and adjacent wall elements with the peripheral edge portions of this panel received in grooves provide-d therefor in each of these respective building construction elements.

This building construction also includes a ceiling consisting of one or more substantially horizontally oriented,

parallel ceiling beams attached at their opposite ends to the top beams of two opposite walls with at least one wall panel located in the space bounded by the top beams and adjacent ceiling beams, the peripheral edge portions of the wall panel being received within grooves provided therefor in the top beams and the ceiling beams.

Specific description For a more specific description of this invention reference is now made to the drawings in general and particularly to FIGURE 1. Building construction 10 consists of top beams 12 and bottom beams 14, separated vertically and connected together by vertical interior wall elements 16, exterior wall elements 18 and corner elements 28. Top beams 12 are connected in end to end relation in the outline of the walls of this construction. Likewise bottom beams 14 are connected in end to end relation in the same outline. Interior and exterior wall panels 22 and 24, respectively, are located within the spaces bounded by the top beam 12, bottom beam 14, corner elements 20 and adjacent interior and exterior wall elements 16 and 18, respectively, retained therein in a manner to be described hereinafter.

Top beam 12 is provided on it bottom surface with two downwardly opening longitudinal parallel interior and exterior grooves 26 and 28, respectively, on its inwardly exposed side surface with longitudinal groove 29. Bot? torn beam 14 is provided on its top surface with two characters designate corresponding parts in the sever-a1 views.

FIGURE 1 is a partial interior view of a structure formed of the building construction of this invention.

FIGURE 2 is an interior view of a structure, including an interior partition wall, formed of the building construction of this invention.

FIGURE 3 is an exterior view of an exterior wall element of the building construction of this invention.

FIGURE 4 is an exterior view of an interior wall element of the building construction of this invention.

, one side with longitudinal parallel interior and exterior grooves 37 and 38, respectively, and on an adjacent side with longitudinal parallel interior and exterior grooves 39 and 40. As is best seen inFIGURE 7, grooves 37 and 38 are deeper than grooves 39 and 40 for reasons to be more fully described hereinafter.

Grooves 26, 30, 34, and 39 (or 37) are in registering relation to one another so as to receive and retain therein the peripheral edge portions of interior wall panels 22. Likewise, grooves 28, 32, 36 and 46 (or 38) are in registering relation to one another so as to receive and retain therein the peripheral edge portions of exterior wall panels 24.

As is best seen in FIGURE 4, interior wall element 16 is preferably symmetrical in shape, having a substantially rectangular transverse cross section except for side grooves 34. Wall element 16 is provided on each end with a lip extension 41 to be received within the grooves 26 and 30 provided therefore in top and bottom beams 12 and 14, respectively. Referring now to FIGURE 3, exterior wall element 18 is preferably provided with an exteriorly exposed enlarged side portion 43 to provide strength for supporting the structure. Furthermore, wall element 18 is provided on each end with lip extensions 19 to be received within groove 28 and 32 provided therefore in top and bottom beams 12 and 14, respectively.

Openings, such as door or window openings, are easily formed using the building elements of this building construction 10. As is shown in FIGURE 1 a door casement is formed of two spaced apart vertically extending parallel casement members 42, attached at their upper ends to the top beam 12 and attached at their lower ends to the bottom beam 14. Of course, a section of the bottom beam 14 will be omitted in the space between the bottom ends of casement members 42. A header member 44 extends between casement members 42 with its opposite ends slidably received within transverse slots 43 in the inwardly exposed surfaces of members 42, near their respective upper ends. I

Each casement member 42 is provided on its surface facing in the direction opposite from the opening with parallel longitudinally extending interior and exterior grooves 46 and 48, respectively, for receiving therein a peripheral edge portion of interior and exterior wall panels 22 and 24, respectively, adjacent thereto. The header member 44 is provided on its top surface with upwardly opening parallel longitudinal interior and exterior grooves 50 and 52, respectively, for receiving therein the bottom peripheral edge portion of interior and exterior short wall panels 23 and 25, respectively. Wall panels 23 and 25 extend upwardly far enough that their upper peripheral edge portions extend into interior and exterior grooves 26 and 28, respectively, of top beam 12.

A relatively short L-shaped pacer 54 is located at each side edge of panels 23 and 25, interiorly and exteriorly of panels 23 and 25, respectively. One leg portion of a spacer 54 extends into the space between the side edge of one of the panels 23 or 25 and the adjacent surface of a casement member 42 with the other leg portion extending parallel and adjacent to the exposed surface of the peripheral portion of the panel 23 or 25. Spacers 54 function primarily to fill and hide the gaps between the respective side edges of panels 23 and 25 and the adjacent surfaces of casement members 42.

It should be noted that a window opening is easily assembled by first assembling a door opening as above described,.then connecting a second header'member (not shown) between the casement members, near their respective lower ends. The second header member is oriented with its grooved surface presented downward so as to accommodate second interior and exterior wall panels (not shown). Of course, the second header member will serve as the sill for a conventional window sash. When forming a window opening as just described the bottom beam 14 extends through the space between casement members 42'so that the second interior and exterior short wall panels can extend downwardly into grooves 30 and 32, respectively, of bottom beam 14.

Referring now to FIGURE *2, there is shown building construction 10 including partition wall 56 and ceiling 58. Partition wall 56 consists of a top beam 6t} and a bottom beam 62, separated vertically from and con nected to the top beam 60 by parallel spaced apart wall elements 16 and a wall tie-in element 64, with single wall panels 22 located in the spaces bounded by the top beam, the bottom beam, wall tie-in element and adjacent wall elements 16 in partition wall 56. Partition wall top and bottom beams 60 and 62, respectively, are connected to top and bottom beams 12 and 14, respectively, in a manner well known to the building art, so as to place grooves 29 and 6 8 in communication and grooves 30 and 70 in communication.

Top beam 60 is substantially similar in construction to top beam 12 except that it is provided with two horizontally and oppositely opening longitudinal grooves 66 and only one downwardly opening longitudinal groove 68. Likewise, bottom beam 62 is similar to bottom beam 14 except that it has only a single upwardly opening longitudinal groove 70. Furthermore, wall tie-in element 64 is similar to interior wall elements 16 except that element 64 is provided on its internally exposed surface with a longitudinal inwardly opening groove 72. Grooves 34,- 68, 70 and 72 are in registering relation to receive and retain therein the peripheral edge portions of wall panels 22.

It should be noted that wall tie-in element 64 is built into the exterior wall 65 of building construction 10 thereby effectively connected partition wall 56 to exterior wall 65.

Interior wall elements 16 are also employed as ceiling beams for the ceiling 58. Spaced apart parallel elements 16 extend between two opposite top beams 12 (only one of which is shown in FIGURE 2) with lips 76 extending into grooves 29 in the side surfaces of the top beams 12. Wall panels 22 are then positioned within the spaces bounded by the top beams 12, partition wall top beam 647 and adjacent elements 16. Grooves 29, 34, and 66 in top beam 12, wall element 16 and partition wall top beam 60, respectively, are in registering relation to receive and retain therein the peripheral edge portions of wall panels 23 in ceiling 58.

Method of assembly In assembly the building construction 10, the bottom beams are initially laid out upon the conventional construction base, such as floor 84 in the outline of the walls to be constructed. A separate vertical corner element 20" is then attached at its bottom end to the bottom beam 12 at each corner of the construction. Top beams 14 arethen attached to the upper ends of the corner elements 28 in the same outline as the bottom beams 12. An exterior Wall panel 24 is then inclined slightly to the vertical and its' top peripheral edge portion is inserted into the exterior groove 28 of top beam 12, adjacent the side of a corner element 20 provided with the deeper grooves 39 and 40. The height of panel 24 is predetermined to allow it to then 'be pivoted into a vertical position thereby lining its bottom peripheral edge up with the exterior groove 32 of bottom beam 14. Panel 24 is then dropped into groove 32 and the panel is slid toward the adjacent corner element 20 until 'its peripheral edge portion extends inwardly to the maximum depth of groove 46 in corner element 20.

An external wall element 18 is then inclined slightly to the vertical and the lip 45 on the upper end thereof is inserted into exterior groove 28 of top beam 12, adjacent the exposed edge of wall panel 24, already positioned between top and bottom beams 12 and 14, respectively. Wall element 18 is then pivoted until the lip 45 on the bottom end thereof registers with exterior groove 32 of bot tom beam 14 at which time element 18 is allowed to move downwardly relative to bottom beam 14 until the bottom end of element 18 contacts the top surface of bottom beam 14 with bottom lip 45 extending into groove 32. External Wall element 18 is then slid toward the already assembled wall panel 24 until the adjacent peripheral edge portion of panel 24 extends into the groove 36 inside of element 18 adjacent thereto.

Exterior wall panels 24 and exterior wall elements 18 are then assembled across the full length of the wall in the manner just described. The transverse width of panels 24 is predetermined so that the last panel to be assembled will just fit into the last remaining space between top and bottom beams 12 and 14 respectively, wall element 18 and adjacent corner element 20. When the last panel 24 has been assembled, the entire wall consisting of elements 18 and panels 24 is slid longitudinally away from the deep grooves 37 and 38 of the first corner element 20 toward the shallow grooves 39 and 40 of the second corner element 20 until the exposed peripheral edge portion of the last panel 24 to be assembled, adjacent shallow grooves 40, is received into the maximum depth of groove 40.- Since groove 38 is deeper than groove 40, when the wall consisting of elements 18 and panels 24 is slid toward groove 38 the peripheral edge of panel 24 adjacent groove 38 will not be completely withdrawn therefrom.

Interior wall elements 16 and panels 22 are assembled in the space between top and bottom beams 12 and 14, respectively, in a manner similar to that described above with respect to exterior wall elements 18 and panels 24 thereby producing a hollow core external wall between two corner elements 20.

All of the exterior hollow core walls of this building construction are assembled in the manner just described.

Likewise, the method of assembling an interior partition wall 56 of construction is similar to that of assembling the exterior walls. To allow ceiling 58 to be assembled by this same method the horizontally opening grooves 29 in two adjacent top beams 12 of the construction 10 (or of a room within the construction) are deeper (or shallower) than the horizontally opening grooves in the remaining two walls.

It should be noted that in those walls that include an opening, such as a door or window opening, the wall elements 16 and 18 and panels 22 and 24 assembled from each corner elements 28 toward the opening with the casement members 42 assembled into the walls last. Alternatively, the casement members can be assembled into the wall before the elements 16 and 18 and panels 22 and 24 with the remainder of the construction being assembled afterwards. In this alternate method of assembly the grooves 46 and 48 in the casement member 42 forcing deep grooves 37 and 38 in a corner element 20 must be shallower than grooves 37 and 38 and grooves 46 and 48 in the easement member 42 that forces shallow grooves 39 and 40 in a corner element 20 must be deeper than grooves 39 and 40 so that the method of assembly of this invention can be utilized.

It should be noted that the top and bottom beams 12 and 14, respectively, of building construction can be pretooled to an attractive molding design as shown at 80 and 82 in FIGURES 5 and 6, respectively, so as to minimize the amount of finish work required with this building construction. Also, partition wall top and bottom beams can be similarly tooled when desired.

Although partition wall 56 has been described as being a single wall as compared to the double or hollow core exterior walls, it is contemplated that wall 56 can be assembled as a hollow core wall in the same manner as the exterior walls.

It should furthermore be understood that the walls of this building construction can be assembled in a multiplicity of designs, such as the Wainscot wall panelling 84 in FIGURE 1. Furthermore, the interior and exterior wall panels 22 and 24 can be of the same or different material and/ or shape and design according to the desires of the builder. As is shown in FIGURE 1 the panels 22 and 24 are of flat metallic stock whereas the panels used in the Wainscot panelling 84 are wood, the panels 22-A and 24-A are made of a substantially flat transparent material such as glass and the panels 22-B and 24-B are corrugated.

It is also contemplated that the various elements of this building construction can be either produced in sizes and shapes according to the pre-planed dimensions of a structure to be constructed thereby, or can be produced in standard sizes and shapes and later cut to the required size on the job site.

This building construction can also be used to form a second new wall covering a pre-existing old wall. In so doing the bottom beam 14 or partition wall bottom beam 62 (according to whether a hollow core or a single wall is desired) would be either attached to the base of the old wall or attached to the floor, near to or in contact with the base of the old wall. The remainder of this second wall is then assembled as above described.

As can best be seen in FIGURE 7 a hollow core wall produced with the building construction of this invention has a continuous space between the interior and exterior wall panels 22 and 24, respectively, and the interior and exterior wall elements 16 and 18, respectively, extending throughout the length of the wall from one corner element 20. Furthermore, with this building construction there is no necessity for additional braces within this between the interior and exterior wall panels. Therefore, there is no obstruction between interior and exterior wall panels that would interfere with the installation of plumbing connections, electrical wiring, insulation and the like.

It should be noted that in assembling building construction 10, should it develop that the wall to be formed .thereby is longer than the wall elements 16 and/ or 18, it is contemplated that one end of the wall element can be provided with a female groove or slot for receiving therein the male lip extension 41 or 45 thereby connecting two elements together to form an elongated element of the same or greater length as the wall.

The invention has been described by references to specific and preferred embodiments. It will be apparent, however, that many modifications can be made without departing from the spirit and scope of the invention.

Accordingly, this invention should be construed not to be limited to the embodiment herein described but should be limited only by the scope of the appended claims.

What is claimed:

1. A building construction for use in forming a multiwalled structure said construction comprising:

a plurality of bottom beams attached in end-to-end relation and laid out in the outline of the walls of said structure, each of said bottom beams provided on its upper surface with parallel longitudinal upwardly opening interior and exterior grooves;

a plurality of top beams attached in end-to-end relation and spaced vertically above said bottom beams, in the same outline as said bottom beams, each of said top beams provided on its lower surface with parallel longitudinal downwardly opening interior and exterior grooves and provided on one of its side surfaces with a longitudinal horizontally opening groove, said interior and exterior grooves in said top beams being deeper than said interior and exterior grooves in said bottom beams;

a plurality of spaced apart vertical interior wall elements attached at their upper ends to said top beams and attached at their lower ends to said bottom beams, each of said interior wall elements provided with two oppositely opening longitudinal grooves and provided on the upper and lower ends thereof with longitudinally extending lips that are received within the interior grooves of said top and bottom beams respectively;

a plurality of spaced apart vertical exterior wall elements attached at their upper ends to said top beams and at their lower ends .to said bottom beams, said exterior wall elements being spaced exteriorly from said interior wall elements and each of said exterior wall elements provided with two oppositely opening longitudinal grooves and provided on the upper and lower ends thereof with longitudinally extending lips that are received within the exterior grooves of said top and bottom beams, respectively;

a vertical corner element located at each corner of said structure, attached at its upper end to said top beam and attached at its lower end to said bottom beam, each of said corner elements provided on at least one side surface with parallel longitudinal interior and exterior grooves;

an interior wall panel located in each of the substantially planar spaces bounded by said bottom beams, said top beams, said corner elements and adjacent inner wall elements with the peripheral edge portions of said interior panel received within said interior grooves within said bottom beams, said top beams and said corner elements and said grooves in said interior wall elements;

an exterior wall panel located in each of the planar spaces bounded by said bottom beams, said top beams, said corner elements and adjacent exterior wall elements with the peripheral edge portions of said exterior panel received within said exterior grooves in said bottom beams, said top beams and said corner elements and said grooves in said exterior wall elements;

a plurality of substantially parallel spaced apart ceiling beams, each ceiling beam provided on each of its two opposite ends with a longitudinally extending lip that is received in said horizontally opening grooves provided in the side surfaces of two opposite top beams, each of said ceiling beams provided with two oppositely and horizontally opening longitudinal grooves;

at least one ceiling panel located in each of the planar spaces bounded by said top beams and adjacent ceiling beams with the peripheral edge portions of said ceiling panel received within said horizontally opening grooves in said top beams and said celing beams.

2. A building construction according to claim 1, wherein at least one each of said interior and adjacent exterior wall panels are transparent.

3. A method of assembling a wall building construction comprising the steps of a positioning a first beam in the outline of a first peripheral edge of said wall, said first beam provided with at least one longitudinal groove opening in a direction parallel to and towards said wall;

attaching one end of a first corner element to said first beam, extending from said first beam in the outline of a second peripheral edge of said wall, said first corner element provided with at least one longitudinal groove registering at one end with said groove in said first beam and opening in a direction parallel to and towards said wall;

attaching one end of a second corner element to said first beam, said second corner element being substantially parallel to said first corner element and separated therefrom and extending from said first beam in the outline of a third peripheral edge of said wall, said second corner element provided with at least one longitudinal groove registering at one end with said groove in said first beam and opening in a direction parallel to and towards said wall, said groove in said second corner element being shallower than said groove in said first corner element:

attaching a second beam to the free ends of said first and second corner elements in the outline of a fourth peripheral edge of said wall thereby producing a four sided wall space bounded by said first and second beams and said first and second corner elements, said second beam provided with at least one longitudinal groove opening in a direction parallel to and towards said wall, said groove in said second beam being shallower;

aligning a first peripheral edge of at least one first Wall panel, inclined slightly to the plane of said wall with said first peripheral edge lying within the plane of said wall, with said groove in said first beam;

inserting said first peripheral edge of said first wall panel into said groove in said first beam;

pivoting said first wall panel into the plane of said wall to align a second peripheral edge of said first wall panel, opposite said first peripheral edge, with said second beam, the length of said first wall panel in the direction from said first beam to said second beam being greater than the distance between said first and said second beams plus the depth of said groove in said second beam and less than the distance between said first and said second beams plus the depth of said groove in said first beam, said first wall panel being less in width than the distance between said first and said second corner elements;

moving said first wall panel lengthwise to insert said second peripheral edge into said groove in said second beam;

moving said first wall panel toward said first corner element to insert a third peripheral edge of said first wall panel into said groove provided in said first corner element;

aligning a first longitudinal lip extension on one end of at least one elongated wall element, inclined slightly to the plane of said wall, with said groove in said first beam, adjacent the forth peripheral edge of said first wall panel, said wall elements being approximately the same length as said first wall panel;

inserting said first lip extension into said groove in said first beam;

pivoting said wall element into the plane of said wall to align a second longitudinal lip extension on the other end of said wall element with said groove in said second beam;

moving said wall element lengthwise to insert said second lip into said groove in said second beam;

moving said wall element toward said first wall panel until said fourth peripheral edge of said first wall panel is received within a first longitudinal groove provided therefore in said wall element;

positioning at least one second wall panel in the portion of said wall space, adjacent said second corner element, not occupied by said first wall panel and said wall element in the same manner as described with reference to said first wall panel, with a first and a second peripheral edge of said second wall panel received in said grooves in said first and said second beams, respectively, said second wall panel having a length approximately equal to the length of said first wall panel and having a width slightly less than the distance between said wall element and said second corner element;

moving said first and said second wall panels and said wall element toward said second corner element until a third peripheral edge of said second wall panel is received in a second longitudinal groove provided therefore in said wall element and a fourth peripheral edge of said second wall panel is received in said groove in said second corner element.

4. A method of assembling a wall building construction according to claim 3, wherein said first and said second beams and said first and said second corner elements are provided each with addi- :tional longitudinal grooves for receiving therein the adjacent peripheral edges of wall panels adjacent thereto forming a part of additional walls constructed according to the method of claim 3.

9 10 5. A method of assembling a wall building construction FOREIGN PATENTS according to claim 3, wherein said Wall is a side wall of 1,340,186 1963 France a structure- 519,128 1931 Germany.

References Cited by the Examiner 5 ggi x g UNITED STATES PATENTS 110,466 1944 Sweden.

1,343,926 6/1920 Madsen 52-495 I 2,079,635 5/1937 Sharp FRANK L. ABBOTT, Plzmary Examiner. 2,748,592 6/ 1956 Kelly 52-169 R. A. STENZEL, Assistant Examiner.

3,133,322 5/1964 Douglas 52-288 10 

1. A BUILDING CONSTRUCTION FOR USE IN FORMING A MULTIWALLED STRUCTURE SAID CONSTRUCTION COMPRISING: A PLURALITY OF BOTTOM BEAMS ATTACHED IN END-TO-END RELATION AND LAID OUT IN THE OUTLINE OF THE WALLS OF SAID STRUCTURE, EACH OF SAID BOTTOM BEAMS PROVIDED ON ITS UPPER SURFACE WITH PARALLEL LONGITUDINAL UPWARDLY OPENING INTERIOR AND EXTERIOR GROOVES; A PLURALITY OF TOP BEAMS ATTACHED IN END-TO-END RELATION AND SPACED VERTICALLY ABOVE SAID BOTTOM BEAMS, IN THE SAME OUTLINE AS SAID BOTTOM BEAMS, EACH OF SAID TOP BEAMS PROVIDED ON ITS LOWER SURFACE WITH PARALLEL LONGITUDINAL DOWNWARDLY OPENING INTERIOR AND EXTERIOR GROOVES AND PROVIDED ON ONE OF ITS SIDE SURFACES WITH A LONGITUDINAL HORIZONTALLY OPENING GROOVES SAID INTERIOR AND EXTERIOR GROOVES IN SAID TOP BEAMS BEING DEEPER THAN SAID INTERIOR AND EXTERIOR GROOVES IN SAID BOTTOM BEAMS; A PLURALITY OF SPACED APART VERTICAL INTERIOR WALL ELEMENTS ATTACHED AT THEIR UPPER ENDS TO SAID TOP BEAMS AND ATTACHED AT THEIR LOWER ENDS TO SAID BOTTOM BEAMS, EACH OF SAID INTERIOR WALL ELEMENTS PROVIDED WITH TWO OPPOSITELY OPENING LONGITUDINAL GROOVES AND PROVIDED ON THE UPPER AND LOWER ENDS THEREOF WITH LONGITUDINALLY EXTENDING LIPS THAT ARE RECEIVED WITHIN THE INTERIOR GROOVES OF SAID TOP AND BOTTOM BEAMS RESPECTIVELY; A PLURALITY OF SPACED APART VERTICAL EXTERIOR WALL ELEMENTS ATTACHED AT THEIR UPPER ENDS TO SAID TOP BEAMS AND AT THEIR LOWER ENDS TO SAID BOTTOM BEAMS, SAID EXTERIOR WALL ELEMENTS BEING SPACED EXTERIORLY FROM SAID INTERIOR WALL ELEMENTS AND EACH OF SAID EXTERIOR WALL ELEMENTS PROVIDED WITH TWO OPPOSITELY OPENING LONGITUDINAL GROOVES AND PROVIDED ON THE UPPER AND LOWER ENDS THEREOF WITH LONGITUDINALLY EXTENDING LIPS 